NCSC Sample Instructional Unit - Elementary Measurement Lesson 4 Perimeter and Area NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

Perimeter – “Distance Around” square = polygon with four equal sides and four 90º angles 2 inches 2 inches 2 inches Remind students that with a square, all sides are the same length. (Click) Click four times to show that each side of this square is 2 inches long. Tell students that to find the perimeter of a square, all they have to do is add up the lengths of the four sides. (Click) Remind students that repeated addition is the same thing as multiplication, so a faster way to find perimeter of a square is to multiply the length of one side by 4 since there are 4 sides and they each have the same length. (Click for the animation showing how to multiply to find perimeter.) Point out that this particular square was measured in inches, and so the answer is also expressed in inches. 2 inches Perimeter: 2 + 2 + 2 + 2 = 8 inches 2 x 4 sides = 8 inches NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

Perimeter – “Distance Around” square = polygon with four equal sides and four 90º angles Perimeter: 5 + 5 + 5 + 5 = 20 in OR 5 x 4 sides = 20 in Tell the students that this is another square. (Click) Tell the students that here we are only given the length of one side but that, that’s all we need given that we know all four sides of a square are equal. (Click four times to show the outline of each side.) (Click) Again, show the students that perimeter can be calculated by adding the length of each side or by multiplying the length of one side by 4. Point out that this square, too, was measured in inches and so the answer was given in inches. 5 in NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

Perimeter – “Distance Around” rectangle = polygon with four 90º angles and opposite sides of equal lengths 6 inches 2 inches 2 inches 6 inches Remind students that with a rectangles, opposite sides have the same length. (Click) Click twice to show the length of two of the sides of this rectangle measures 2 inches each. Click twice more to show the width of the other two sides measures 6 inches each. Remind students that to find the perimeter of a square, all they have to do is add up all four sides. (Click) Remind students that repeated addition is the same thing as multiplication, so a faster way to find perimeter of a rectangle is to multiply the length by 2, multiply the width by 2, then add the products. (Click) Point out that this particular square was measured in inches, and so the answer is also expressed in inches. Perimeter: 2 + 6 + 2 + 6 = 16 inches 2 x 2 = 4 2 x 6 = 12 4 + 12 = 16 inches NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

Perimeter – “Distance Around” rectangle = polygon with four 90º angles and opposite sides of equal lengths 1 inch 7 inches Remind students that with a rectangles, opposite sides have the same length. (Click) Click to show that here we are only told the length of one of the sides is 1 inch. Click to show that here we are only told the width of one of the sides is 7 inch. Point out that we can still find the perimeter since we know that with a rectangle, opposite sides are equal. Click to show that the perimeter of this rectangle can be determined by doubling the length, doubling the width, then adding. Point out that this particular square was measured in inches, and so the answer is also expressed in inches. Perimeter: 1 x 2 = 2 7 x 2 = 14 2 + 14 = 16 inches NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

NCSC Sample Instructional Unit - Elementary Measurement Lesson 4 Area – “Space Inside” 4 inches 1 in 1 in 1 in 1 in 1 in 1 in 1 in 1 in 4 inches 16 square inches 1 in 1 in 1 in 1 in Tell students that now they are going to learn how to find the area of a square. Remind students that area has to do with the amount of space inside a figure. (Click) Tell the students that one way to find area is to fill the inside of the figure with square tiles. In this case, they are 1-in square tiles. Click and have the students count up the number of 1-in squares it takes to fill the square. (16) Click to show the students how the length of one side is 4 inches. Remind the students that in a square, all sides are equal. (Click again) Show the students that the width is also 4 inches. Click to show how area can be calculated by multiplying the length times the width. Point out that when calculating area, the answer is expressed in square units since area refers to the amount of small squares it takes to fill the larger one. 1 in 1 in 1 in 1 in Area = Length x Width 4 x 4 = 16 in2 NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

NCSC Sample Instructional Unit - Elementary Measurement Lesson 4 Area – “Space Inside” 2 inches 1 in 1 in 1 in 1 in 6 square inches 3 inches 1 in 1 in Tell students that now they are going to learn how to find the area of a rectangle. Remind students that area has to do with the amount of space inside a figure. (Click) Remind the students that one way to find area is to fill the inside of the figure with square tiles. Again, in this case, they are 1-in square tiles. Click and have the students count up the number of 1-in squares it takes to fill the square. (6) Click to show the students how the length of one side is 3 inches and the length of one side is 2 inches. Click to show how area can be calculated by multiplying the length times the width. Point out that when calculating area, the answer is expressed in square units since area refers to the amount of small squares it takes to fill the larger one. Area = Length x Width 3 x 2 = 6 in2 NCSC Sample Instructional Unit - Elementary Measurement Lesson 4

NCSC Sample Instructional Unit - Elementary Measurement Lesson 4 Summary Perimeter – Add up all of the sides Don’t forget to include the units with your answer. Area – Multiply the length times the width Answer needs to be in square units (such as in2) NCSC Sample Instructional Unit - Elementary Measurement Lesson 4